The present invention relates to glass production and more particularly to a glass melting furnace and the operation thereof.
In the manufacture of glass in tank furnaces, unmelted batch is fed onto an established bath of molten glass at one end of the furnace where it is melted, the molten glass, which forms from the batch, passes down the furnace from the melting area, through refining and conditioning zones, and is drawn off from the furnace to be processed in any known manner.
It is difficult in practice to obtain completely homogeneous glass, free from undissolved solids and gases, particularly at high tank loads when time and temperature in a particular zone are limited by furnace design and refractory constraints, the glass produced is generally heterogeneous in composition, to a greater or lesser degree, dependent upon the efficiency with which melting and subsequent operations are accomplished. Glass, varying in composition, forms in layers in the furnace, these layers being subject to convective and other flows imposed by the furnace operation, design and other physical operations carried out on the glass. In general in the final product, the plates are parallel to the glass surfaces but there is deviation from this parallel state in areas which have been subject to the above described modifying conditions. Where the plates cease to be parallel to the faces of the glass optical faults occur which are termed ream.